This invention relates generally to blind rivets and more particularly to blind rivets adapted to lock in place and seal the openings in one or more apertured sheets whether or not there are spaces intervening between the sheets.
Blind rivets, that is rivets applied from one side of sheets of material without access to the other or hidden side of the sheet, are well known. Many of the prior art blind rivets comprise assemblies used to indirectly obtain access to the hidden side of the sheet. Still others of the prior art depend upon their cutting or forming an aperture as they are inserted and achieve their locking action by a grip that is analogous to that of a screw in sheet material. While the known blind rivets succeed in securing materials together, their basic design results in a number of limitations on their use in certain mass production fields and particularly in fields where inert, sterile applications are required. The multiple part blind rivets tend to be relatively costly, are easily contaminated and make imperfect seals. The "cutting" type are also expensive in that hardened materials are necessary and, the sharp cutting flutes tend to encourage the accumulation of contaminants and these also tend to be unable to achieve simple perfect seals.